


























































































































































































































































































































































































































































































































Class T'L r ?c3 

Book.__ l 

fiprigitT P- )1I7 



COPYRIGHT DEPOSm 






















t 


THE CURTISS 
STANDARD MODEL V-2 
AERONAUTICAL MOTOR 


HAND BOOK 



1917 


CURTISS AEROPLANE AND MOTOR CORPORATION 





T1-703 
,Cg$3 
f 9i7 


COPYRIGHT 1917 

* ' BY 

CURTISS AEROPLANE AND MOTOR CORPORATION 



V 


AUG 16 1317 


©CU471664 
'HP ( , 

ii-T-tfiotf- 



TABLE OF CONTENTS 

Subject ' Page 

Specifications.4 

Installation Dimensions.5 

Unpacking.6 

Setting Up. 7 

Starting the Motor.8 

Ignition. 9 

Carburetion.13 

Lubrication.13 

Cooling.14 

Inspection and Overhauling.14 

The Trouble Chart .19 

Index to Motor Drawings.25 


♦ 














4 Curtiss Aeroplane and Motor Corporation 


V-2 MOTOR 

GENERAL SPECIFICATIONS 

Type.“ Vee,” 8 cylinder, 4 Stroke Cycle 

Bore and Stroke.5 in. x 7 in. 

Horsepower at 1400 R. P. M. (Rated).200 

Horsepower at 1400 R. P. M. (Brake).210 

Normal Speed. 1400 R. P. M. 

Cooling.Water 

Weight (Complete). 725 lbs. 

Ignition . . Two Independent, 8 cylinder, High Tension Magnetos 

Lubrication. Force Feed 

Carburetion .... Two Carburetors, one on each side of motor 

Fuel Consumption (normal), per H. P. Hour. 0.54 lbs. 

Oil Consumption (normal), per H. P. Hour. 0.03 lbs. 

Capacity of Oil Reservoir. 1848 cu. in. 

INSTALLATION DIMENSIONS 

Overall Length.67i|- in. 

Overall Width.37 in. 

Overall Depth.34 T 3 ^ in. 

Width at Bed (Inside Supports).14J in. 

Width at Bed (Center to Center of Bolts).15f in. 

Height from Bed.20j in. 

Depth from Bed. 

Bed Bolts (Center to Center).9 in. 






















V-2 Hand Book 


5 




















































































6 Curtiss Aeroplane and Motor Corporation 


V-2 MOTOR HAND BOOK 


1. UNPACKING 

The Curtiss Model V-2 motor is shipped from the factory com¬ 
pletely enclosed in a substantial box. The motor is bolted to two 
supports or sills fastened and braced to the bottom of the box. 
To unpack, eight lag screws must be removed from the base of the 
box, allowing the cover to be lifted off intact. (Fig. II.) 

To hoist the motor from the sills either of two methods may be 
used. 

The first method requires two solid metal bars of at least }" 
diameter and four wires or cables of equal length and with a loop 
on each end. 

The two bars should be placed one on each side of the motor, 
bearing against the water jacket wall just under the water inlet 
pipes. These bars are supported by one of the cables passing 
between the first two and last two cylinders on each side. The 
lower loops of the cables pass around the bar and the upper loops 
are all passed over the hoisting hook. 

The second method consists of passing a rope or cable sling 
under the nose, well up toward the cylinders, and another around 
the bottom of the front gear case—not the water pump. Care must 
be taken in this case to prevent the cable from fouling any tubing 
or push rods. A wooden block should be used between the cables 
of the front sling to hold them away from the magnetos. 

Before shipment the Curtiss motors are slushed with vaseline to 
prevent rusting or corroding enroute. Leave the wooden plugs in 
the valve cages, and the corks in the water lines and carburetor 
operating shaft stuffing boxes, until the motor is anchored to its bed 
in the machine. A spray of gasoline under air pressure will wash 
the vaseline from the motor. This can be done with an atomizer. 
Care must be taken to keep the gasoline out of the magnetos, other¬ 
wise there will be danger of fire w r hen the motor is started. 





Fig. II. Hoisting Motor From Shipping Box 












V-2 Hand Book 


7 


Do NOT ATTEMPT TO EVEN PARTIALLY REST THE WEIGHT OF 
THE MOTOR ON THE LOWER HALF OF THE CRANK CASE, OR ON 
ANY PART OTHER THAN THE SUPPORTING ARMS. 

2. SETTING UP 

Study carefully the installation diagram shown on the “Data 
Sheet,” Fig. No. I and the Motor Assembly Drawings, Figs. V 
and VI. 

The bearers (96) should be 2 inches wide by 5 inches deep, 
preferably of laminated hard wood, and placed 14^ inches apart. 
They must be well and equally braced at forward and rear ends 
and at the mid-section of the motor, to avoid undesirable vibration. 

The ten arms of the motor base are drilled for ^-inch bolts, and 
no other size should be used. The bearers should be wrapped 
with a thin strip of copper under each supporting arm. After the 
motor is placed in position a feeler gauge should be used to deter¬ 
mine if all the arms bear equally. Any inequalities found must be 
corrected before tightening the engine bed bolts. 

(a) Anchoring the Motor: Put the bolts in from the bottom, 
with a large washer under the head of each, so the head cannot 
cut into the wood. On every bolt use a castellated nut and cotter 
pin so the bolt will not work loose. Set the motor in place and 
fasten, before attaching any auxiliary apparatus, such as carbu¬ 
retors (54), etc. 

( b ) Magnetos and Wiring: Connect the wires from each dis¬ 
tributor according to the wiring diagram shown in Fig. III. One 
wire from the ignition switch should be connected to the motor 
body for ground connection and the other two to the posts on the 
breaker boxes of the magnetos. All connections should be tight 
and firm. The switches should be left open until ready to start 
the motor. 

(c) Carburetors and Gasoline Line: Remove the wooden plugs 
and attach the carburetor (54) and manifolds (52). Carburetor 
braces (55), which fasten to the carburetor and the lower half of 



8 Curtiss Aeroplane and Motor Corporation 


the crank case, will be found in the packing box. Do not strain 
the manifold to make it fit these braces, but see that the right-hand 
induction pipe and carburetor are on the right-hand side as origin¬ 
ally fitted. By leaving the two bolts, which fasten the induction 
pipe to the manifold, a little bit loose, and by shifting the joint, the 
brace can be made to fit. 

When the throttle controls are attached to the carburetor the two 
lower case butterfly throttle valves should close simultaneously. 
Fuel connections from the fuel tank to each carburetor should be 
at least §" inside diameter. 

Fill the gasoline tanks, open the valves connecting the tanks to the 
carburetors and inspect for leaks and for proper float action. It is 
desirable that satisfactory strainers and water separators be located 
between tank and carburetors. Separate lines should feed each car¬ 
buretor from the tank. Each line should be fitted with a spring loop. 

( d) Oil Reservoir: Fill the oil reservoir through the filler pipe 
(69) located between the two cylinder banks. Use a light, high 
grade oil. The recommended lubricant is one-half Castor and 
one-half Mobil “A” oil. 

(e) Cooling System: Fill the cooling system with water through 
the radiator filler pipe and turn the crankshaft one or two revolu¬ 
tions to eliminate any air pockets. Particular care should be taken 
to insure tight connections between radiator outlet and pump 
inlet (80) as leakage here will permit air to be drawn in, displacing 
water and possibly causing overheating of the motor. 

( f ) Oiling Exposed Parts: Oil all exposed parts, as rocker arms 
(31, 32), valve stems, etc. The oil holes in the rocker arms (67) 
will hold oil enough to last for several hours running. 

3. STARTING THE MOTOR 

(a) Starting by Hand: Always retard the spark part way, to 
prevent back-firing, by pulling back the wire attached to the spark 
advance lever on the breaker box (44). Failure to retard the spark 
may result in serious injury to the operator. 



V-2 Hand Book 


9 


Open the cock leading from the gasoline tank to the car¬ 
buretor. 

With the ignition switch “off” prime the motor by squirting a 
little gasoline in the small hole in the top of each exhaust valve 
cage (37). Turn the propeller backwards two revolutions to draw 
the gasoline into the cylinders. 

Turn on the ignition switch with the throttle partly open and 
give a quick, strong pull on the propeller. As soon as the motor is 
started advance the spark by releasing the retard wire. 

(6) Let the motor run on low speed for three to five minutes in 
order to establish oil circulation in all bearings. The pressure as 
indicated bv the oil pressure gauge should be about 25 pounds at 
500 R. P. M., and from 70 to 80 pounds at 1400 R. P. M. 

(c) Warming up the Motor: As soon as all parts are performing 
properly the throttle may be opened gradually for warming up 
before flight. 

Note: The auxiliary air valves on the carburetor barrels are for 
use in altitude flying and must be closed when running the motor 
on the ground. 

(i d) Stopping the Motor: When the motor has been running at 
high power it should be slowed down gradually, then allowed to 
idle a few minutes before stopping. This insures a more uniform 
cooling and increases the life of the valve seats. 

4. IGNITION 

(a) The ignition on this type of engine is by two independent, 
high tension, single spark magneto systems. 

The firing order and cylinder arrangement is as shown on the 
Wiring Diagram, Fig. No. III. 

Ignition troubles are usually traced to faulty spark plugs (46). 
A common cause of spark plug failure lies in the burning away of 
the electrodes, due to intensity of the spark and the widening of 
the gap. This will cause missing at low speeds. The spark plug 
may be tested by connecting it up with its terminal and laying it 



10 Curtiss Aeroplane and Motor Corporation 


on the motor for ground connection. A bright spark should jump 
across the terminals when the motor is turned over briskly. 

All gasoline lines should be carefully shut off before this opera¬ 
tion. 

(6) Trouble with the magneto (41) itself is sometimes due to 
dirt and over-lubrication. If it is thought that the motor is not 
operating properly it is best to test several of the spark plugs by 
the above method before doing anything further. Should no spark 
appear as the several plugs are tested, detach the switch wire from 
the magneto terminal on the interrupter housing-cover (44) and 
test the plugs again. A spark under these conditions will indicate 
a short circuit in either the switch or the switch cable. If there is 
no spark the interrupter should be inspected—care being taken to 
see that the platinum points are clean and smooth and that the 
interrupter lever (43) moves freely on its pivot. If the spark still 
fails, remove the bonnet from the shaft end of the magneto, thus 
exposing the safety spark gap. Turn the motor over rapidly. If a 
spark is seen in the safety spark gap the fault will be found not in 
the magneto but in the distributor, in the spark plug cables, or in 
the spark plugs themselves. If no spark is visible in the safety 
spark gap the trouble is internal and the magneto must be returned 
to the manufacturer for repairs. Under no conditions should the 
magneto be taken apart beyond the removal of the interrupter, the 
distributor plate and the cover on the shaft end. Nothing favorable 
can be accomplished by removing the end plates of the magneto 
and permanent injury is almost sure to result. 

The inside of the commutator should be kept clean and lubri¬ 
cated with cylinder oil, not in too large quantities, however. The 
lubricant recommended is a mixture of one-half Castor oil and 
one-half Mobil “A” oil. Graphite should never be used on the 
commutator. 

Lift out the distributor plate occasionally without disarranging 
the wiring, and remove any accumulation of oil, dirt or moisture. 

(c) The retiming or checking of the magneto should be done by 



V-2 Hand Book 


11 



Fig. III. Clockwise Motor Wiring Diagram 




















































































12 Curtiss Aeroplane and Motor Corporation 



Fig. Ill (a). Anti-Clockwise Motor Wiring Diagram 






















































































V-2 Hand Book 


13 


the l folIowin S method > and should be done only after all valves 
have been set and timed. (See 8-b.) 

Turn the motor in the direction of rotation until the intake valve 
(39) of No. 1 cylinder has closed; then turn the motor in the same 
direction until the piston (86) of No. 1 cylinder is on top dead 
center; then turn the motor backward until the piston of No. 1 
cylinder is 2 Ys2 inch from top center. With the spark advance 
lever at position of full advance, turn the armature of the magneto 
in the direction of its rotation (it is the same as that of the crank¬ 
shaft) until the distributor brush is on No. 1 segment with the breaker 
points just ready to open. 

Put on the magneto gear (45), being careful to line up the key- 
ways, and fasten. This should bring the firing point of all cylinders 
to about 32 degrees before top center. 

5. CARBURETION 

The carburetion on the motor is by two lj-inch carburetors 
placed one on each side, and each feeding to one bank of cylinders. 

Each intake pipe is fitted with a water manifold, taking the hot 
water from the cylinder jackets through a by-pass. 

If adjustment is found necessary it should be attempted only 
by one thoroughly competent and strictly according to the instruc¬ 
tion pamphlet issued by the maker of the carburetor. A lost or 
damaged pamphlet will be replaced on request. It will be well to 
give the name and model of the carburetor when making enquiry. 

6. LUBRICATION 

The oiling system is full force feed. One gear pump (61) forces 
the oil from the oil sump (64) in the crankcase to all bearings at 
considerable pressure. 

From the pump the circulation of the oil is to the rear of the 
hollow camshaft (22), through shaft to all camshaft bearings; 
through passages in the supporting webs (72) to the crankshaft 
bearings, etc., to the crank pin bearings (4). Tubes on the con- 



14 Curtiss Aeroplane and Motor Corporation 


necting rods conduct the oil to the piston pin bearings (92) and 
through the hollow pin to the cylinder walls (91). Surplus oil 
returns to the top of the horizontal oil pan partition (66). 

A pressure regulator valve in the outlet from the pump limits 
the pressure at which the oil is delivered to the cam shaft, by passing 
part of the oil into the space inside the oil screen. The pressure 
may be altered by changing the thickness of the fiber washer under 
the head of the screw which bears against the pressure regulating 
valve spring. 

Two other gear pumps take the oil from above the horizontal 
partition through two pipes, one in front and the other in the rear, 
and after screening it pass it into the sump. This arrangement 
insures positive lubrication and keeps the crankcase clear of oil 
which would otherwise flood the cylinder when the motor is at an 
angle. 

7. COOLING 

A single centrifugal water pump (76) forces the water circulation 
through the cooling system. From the pump two pipes lead, one 
on each side, to the water inlet pipe. Branch pipes lead off to the 
lower outside of each cylinder. The water, after heating, rises to 
the upper inside of the cylinder jackets and through two other 
manifolds to the top of the radiator. 

8. INSPECTION AND OVERHAULING 

Each motor should have a complete inspection at the end of 
every fifty running hours. To do this properly it must be com¬ 
pletely dismantled. 

When new, the machine should not be run for more than five 
hours without thoroughly draining off all oil and carefully cleaning 
the strainer. This procedure should be repeated at the end of the 
second five-hour period of operation, and then at the end of the 
next ten hours. 

(a) Grinding the Valves: The same procedure used in the 
factory should be followed as nearly as possible in the field. Only 



I 


V-2 Hand Book 15 



L /ret-'rr Mr*. 

Fig. IV. Oiling Diagram 









































































































































16 Curtiss Aeroplane and Motor Corporation 


one who is thoroughly familiar with this process should undertake 
to grind the valves, unless it is impossible to get an expert at the 
time. A good valve grinding compound should be used, such as 
“Clover Leaf” or equivalent. 

Before removing the cages (37, 38) mark the cage and cylinder 
head for accurate relocation. Clean the valve face and seat and 
test in three positions for gasoline leakage with the cage full of 
gasoline. Lap in until gasoline tight in three positions and remove 
the shoulders caused by grinding. Reassemble with the cage and 
test again for gasoline leakage. The valves must be lapped until 
perfectly tight. 

( b ) Setting and Timing the Valves: The valves are timed after 
the motor is completely assembled except for the camshaft gear 
(21) and the gear case cover. 

Set the inlet tappet clearance (97) to .020 inches and the exhaust 
tappet clearance (98) to .025 inches. 

Turn the crankshaft in the direction of rotation until No. 1 • 
piston is on top dead center. Turn the camshaft in its direction 
of rotation (opposite to that of the crankshaft) until the exhaust 
valve of No. 1 cylinder has just closed. Put on the camshaft gear, 
being careful to line up the keyways in gear and shaft, insert key 
and fasten. 

Thus set and timed, the inlet valves will open 12 degrees past 
top center and close 40 degrees after bottom center. The exhaust 
valves will open 46 degrees below bottom center and close on top 
center. These values refer to crankshaft rotation. A variation of 
3 degrees from these values will not be detrimental. 

(c) Bearings: The crankshaft (5) and crank pin bearings (4) 
in these motors are made two or three thousandths of an inch 
larger than the shafts, although tests and experiences have proven 
that four-thousandths is not injurious, whereas one-thousandth 
clearance is not sufficient for the maintenance of a proper oil film. 
If the bearings show traces of dirt or the surface appears flaked, 
the dirt or flakes should be carefully cleaned off, without disturbing 



V-2 Hand Book 


17 


the body of the bearing. Do not undertake to refit the bearings 
tighter unless they are larger than the shaft by more than four- 
thousandths of an inch. 

(d) Carbon Deposit: Any deposit of carbon on pistons (86) or 
cylinders (91) should be carefully scraped off while the motor is 
disassembled. Be careful to clean off any carbon that may have 
fallen onto the cylinder wall or any bearing surface, before reas¬ 
sembling. 

9. THE TROUBLE CHART 

The trouble chart has been prepared to outline the various 
troubles and remedies in a form that will facilitate ready reference. 

A general knowledge of motor troubles is necessary to use the 
chart, as for instance, if the motor is “skipping” or “missing” the 
trouble should be found under the heading of “ Skipping or Irregu¬ 
lar Operation.” If the motor fails to develop power the proper 
section is “Lost Power and Overheating.” It is necessary to be 
able to recognize these main divisions in order to locate the remedy. 

In a great many instances the trouble will be found in the aux¬ 
iliary members of the power plant rather than in the motor. This 
chart, however, only undertakes to include the most common 
troubles of the motor itself. 

On the index to the motor drawings, Figs. V and VI, the numbers 
of the parts on the drawing are found in the first two columns. 
The third column gives the part names. The fourth column con¬ 
tains figures which refer to the section in the trouble chart in which 
each motor part is concerned. 



18 Curtiss Aeroplane and Motor Corporation 


IMPORTANT DONT’S 

1. Don’t forget to inspect the motor thoroughly before starting. 

2. Don’t try to start without oil, water or gasoline; all three are 
vital. 

3. Don’t forget to see that the radiator is full of water. 

4. Don’t get dirt or water into the gasoline. 

5. Don’t get dirt or water into the oil. 

6. Don’t forget to oil all exposed working parts. 

7. Don’t try to start without retarding the magneto; a serious 
accident may result. 

8. Don’t try to start without turning on the switch. 

9. Don’t start the motor with throttle wide open. 

10. Don’t run the motor idle too long; it is not only wasteful but 
harmful. 

11. Don’t forget to watch the lubrication; it is most essential. 

12. Don’t forget that the propeller is the business end of the motor; 
treat it with profound respect, especially when it is in motion. 

13. Don’t cut off the ignition suddenly when the motor is hot; allow 
it to idle a few minutes at low speed before turning off the switch. 

14. Don’t fail to study the trouble chart in this book before you 
adjust anything about the motor. 

15. Don’t develop that destructive disease known as tinkeritis: 
when the motor is working all right let it alone. 

16. Don’t forget a daily inspection of all bolts and nuts; keep them 
well tightened. 

17. Don’t fail to study this instruction book thoroughly. 



V-2 Hand Book 


19 


SKIPPING OR IRREGULAR OPERATION 


Part at 
Fault 

Trouble 

Effect 

Remedy 

1 

Spark Plug 

Loose binding at post 
Leak in threads 
Defective gaskets 

Cracked insulator 

Points too close 
Points too far apart 
Carbon deposit 

Plug too long 

No spark 

Low compression 
Low compression 

Short-circuit 

No spark 

No spark 

No spark 

Pre-ignition 

Tighten terminal 
Screw down tighter 
Replace with new 
plug 

Replace with new 
plug 

Set points apart 
Set points closer 
Clean off points 
and plug 
Change plug 

2 

Combustion 

Chamber 

Carbon deposit 

Pre-ignition 

Remove carbon 

3 

Piston Head 

Carbon deposit 

Crack or blowhole 
(rare) 

Pre-ignition 

Pre-ignition 

Remove carbon 
Replace with new 
piston 

4 

Valve Head 

Warped or pitted on 
seat 

Poor mixture 

Low compression 

True up in lathe 
and grind to seat 
Replace with new 
valve 

5 

Valve Stem 

Binds in guide 

Sticks 

Irregular valve 
action 

Clean guide 
Straighten stem 
Oil 

6 

Valve Spring 

Weakened or broken 

Irregular valve 
action 

Replace with new 

7 

Exhaust 
Valve Seat 

Scored or warped 

Dirty or covered with 

scale 

Valve will not 

close 

Poor mixture 

Poor compression 

Use reseat reamer 

Clean off and 
grind to seat 

8 

Exhaust 
Valve Stem 
Guide 

Warped or carbonized 
Worn guide 

Valve stem sticks 

Low compression 
Poor seating 

Poor mixture 

Clean guide or 
new cage. 

9 

Valve Stem 
Clearance 

Too little 

Too much 

Valve will not shut 
Valve opens late 
and closes early 

Set inlet gap .020 
Set exh. gap .025 

10 

Cam Shaft 
Bearing 

Looseness or wear 

Valves mistimed 

or valve lift 
short 

Replace with new 
bushing. 

11 

Cam 

Worn contour 

Valve lift short 
Valves mistimed 

Replace with new 

cam shaft 



































20 Curtiss Aeroplane and Motor Corporation 


SKIPPING OR IRREGULAR OPERATION—Cont. 


Part at 
Fault 

Trouble 

Effect 

Remedy 

12 

Timing Gear 

Not properly meshed 
Loose on shaft 

Worn or broken tooth 

Valves mistimed 

Valves do not act 

Time properly 
Fasten to shaft 
with key 

Replace with new 
gear 

13 

Cam Follower 
Guide 

Loose on engine base 
Lock pin sheared off 
Worn in bore 

Oil leaks 

Poor valve action 

Fasten securely 
New pin 

New guide or 
bushing 

14 

Cam Follower 

Loose in guide 

Valves mistimed 
Oil leak 

Replace with new 
guide or bush¬ 
ing 

15 

Inlet Valve 

Closes late 

Opens early 

Blow-back in car¬ 
buretor 

Time properly 

16 

Inlet Valve 
Seat 

Warped or pitted 
Does not seat prop¬ 
erly 

Carbon grain under 
seat 

Blow-back in car¬ 
buretor 

Low compression 

Use reseat reamer 

Clean off and 
grind to seat 

17 

Inlet Valve 
Stem Guide 

Worn 

Poor mixture 

Low compression 

Bush or replace 
with new guide 
bushing 

18 

Carburetor 

Weak mixture 

Blow-back in car¬ 
buretor 

Adjust carburetor 
for richer mix¬ 
ture 

19 

Gas Manifold 
Pipe 

Leak at joints 
Defective gasket 
Crack or blowhole 

Poor mixture 

Poor mixture 

Poor mixture 

Stop all leaks 
Replace with new 
Solder blowhole 

20 

Piston 

Walls scored 

Poor suction and 
leak of gas 

Smooth up 

21 

Piston Rings 

Loss of spring 

Loose in grooves 
Worn or broken 

Slots in line 

Poor suction and 
leak of gas 

Poor compression 

Peen rings or re¬ 
place with new 
Loosen rings on 
piston 

22 

Cylinder Wall 

Scored by wristpin 

Scored by lack of oil 

Poor suction and 
leak of gas 

Poor compression 

Lap in cylinder or 
new cylinder 

23 

Valve Spring 
Collar Key 

Broken 

Release spring 

No valve action 

Replace with new 
key 



























V-2 Hand Book 


21 


LOST POWER AND OVERHEATING 


Part at 
Fault 

Trouble 

Effect 

Remedy 

24 

Manifold 

Connections 

Poor mixture in one 
set of cylinders 
with good mixture 
in other set 

Surging or pulsat¬ 
ing 

Tighten connec¬ 
tions 

Put in new gaskets 

25 

Water Pipe 
Joint 

Loose 

Defective gasket 

Loss of water and 
overheating 

Tighten bolts or 
Replace with new 
connection 

26 

Spark Plug 

Loose in threads 
Defective gasket 

Poor compression 
and overheating 

(See No. 1) 

Screw down tight 
Replace with new 

27 

Combustion 

Chamber 

Crack or blowhole j 
Roughness 

Carbon deposit 

Poor compression 

Pre-ignition 

Pre-ignition 

Fill by w r elding or 
Replace with new 
Smooth up 
Remove carbon 

28 

Valve Head 

Warped, scored or 
pitted 

Carbonized or cov¬ 
ered with scale 

Poor compression 

True up in lathe 
and grind to seat 
Scrape off smooth 
with emery 
cloth 

29 

Valve Seat 

W T arped or pitted 
Carbonized or cov¬ 
ered with scale 

| Poor compression 
or blow-back 

Use reseat reamer. 
Clean off and 
grind to seat 

30 

Piston Rings 

Loss of spring 

Loose in groove 

Worn or broken 

Slots in line 

Poor suction, leak 
of gas and over¬ 
heating 

Poor compression 

Peen rings or re¬ 
place with new 
Loosen rings on 
piston 

31 

Piston Rings 

Broken because too 
tight 

Insufficient opening 

Scored cylinder 
walls, overheat¬ 
ing in sump pan 
and poor com¬ 
pression 

Replace scored 
cylinder if 
groove is deep 
Use new rings 

32 

Wrist Pin 

Loose 

Scored cylinder 

Poor compression 

Fasten securely 

Replace scored 
cylinder if 
groove is deep 

33 

Piston Head 

Carbon deposit 

Crack or blowhole 
(rare) 

Pre-ignition 

Poor compression 

Remove carbon 
Replace with new 

34 

Piston 

Binds in cylinder 

W r alls scored or worn 
out of round 

Overheating 

Lap off excess 
metal 

Replace with new 
piston 


































22 Curtiss Aeroplane and Motor Corporation 


LOST POWER AND OVERHEATING—Cont. 


Part at 
Fault 

Trouble 

Effect 

Remedy 

35 

Cylinder 

Wall 

Scored 

Poor lubrication 
causes friction 

Poor compression 
and overheating 

Replace with new 
Lap in cylinder 
Repair oiling sys¬ 
tem 

36 

Cam Shaft 
Drive Gear 

Loose on shaft 

Not properly meshed 
Worn or broken teeth 

Irregular valve 
action 

Fasten to shaft 
Time properly 
Replace with new 

37 

Crank Shaft 

Scored or rough on 
journals 

Sprung 

Overheating 

Overheating 

Smooth up 

Straighten 

38 

Crank Pin 
Bearings and 
Main 
Bearings 

Adjusted too tight 

Defective oiling 

Overheating 

Adjust to running 
clearance 

Clean out oil holes 

39 

Oil Sump 

Insufficient oiling 

Poor oil 

Dirty oil 

Overheating and 
burned-out 
bearings 

Replenish supply 
Use best oil—£ 
Mobile “A”and 
\ Castor Oil 
recommended 
Wash with kero¬ 
sene 

Replace with new 
oil 

40 

Water Space 
and Water 
Pipes 

Clogged with sedi¬ 
ment or scale 

Overheating 

Dissolve and re¬ 
move foreign 
material 

41 

Radiator 

Hose 

Layer of hose ob¬ 
structs opening 

Overheating 

Refit or replace 
with new 

42 

Water Pump 

Impeller loose on 

shaft 

Dirty 

Broken 

Overheating 

Fasten to shaft 
Clean 

Replace with new 


NOISY OPERATION 


43 

Spark Plug 

Leakage 

Hissing 

Screw down tighter 

Replace with new 

44 

Cylinder 

Wall 

Scored 

Knocking 

Smooth up or 
Replace with new 
























V-2 Hand Book 


23 


NOISY OPERATION—Cont. 


Part at 
Fault 

Trouble 

Effect 

Remedy 

45 

Manifold 
Pipe Joints 

Leakage 

Defective gaskets 

Sharp hissing 

Tighten bolts 
Replace with new 

46 

Combustion 

Chamber 

Carbon deposit 

Knocking 

Remove carbon 

47 

Cylinder 

Retaining bolts loose 

Sharp metallic 
knock 

Tighten bolts 

48 

Cam 

Worn contour 

Metallic knock 

Replace with new 

49 

Piston Head 

Carbon deposit 

Knock 

Remove carbon 

50 

Wrist Pin 

Worn 

Loose in piston 

Dull metallic 
knock 

Bush or replace 
pin 

51 

Connecting 

Rod 

Worn at wrist pin or 
crank-shaft 

Side plav in piston 

Distinct knock 

Adjust or replace 
Scrape and fit and 
oil 

52 

Main Crank 
Shaft 
Bearing 

Loose 

Defective lubrication 

Metallic knock 

Squeak 

Fit caps close to 
shaft 

Clean out oil holes 
and oil 

53 

Connecting 
Rod Bearings 

j Loose 

| Excessive play 
i Binding 

Intermittent me¬ 
tallic knock 
Knock and squeak 

Refit 

Reline 

54 

Connecting 
Rod Bolts 
Main Bearing- 
Bolts 

Loose 

Stripped threads 

Sharp knock 

Tighten 

Replace bolts 

55 

Lower Half 
Crank Case 
Bolts 

Loose 

Stripped threads 

Knock and rattle 

Tighten 

New bolts 

56 

Water Jacket 

Covered with scale 
Clogged with dirt 

Knock caused by 
overheating 

Dissolve scale A and 

flush out water 
space with water 
under pressure 

57 

Timing Gears 

Loose 

Worn or broken teeth 
Meshed too deeply 

Metallic knock 
Rattle 

Grinding 

Fasten to shaft 
Replace with new 
gear 

58 

Cam Shaft 
Bearing 

Loose or worn 

Slight knock 

Replace with new 
































































24 Curtiss Aeroplane and Motor Corporation 


NOISY OPERATION—Cont. 


Part at 
Fault 

Trouble 

Effect 

Remedy 

59 

Inlet Valve 
Seat 

Warped or pitted 
Dirty 

Rattle 

Poor compression 
Blow-back 

Use reseat reamer 
Clean off and 
grind to seat 

60 

Inlet Valve 
Spring 

Weak or broken 

Blow-back in car¬ 
buretor 

Replace with new 

61 

Inlet Valve 

Closes late 

Opens early 

Blow-back in car¬ 
buretor 

Time properly 

62 

Valve Stem 
Guide 

Worn or loose 

Rattle or click 

Replace with new 
guide 

63 

Cam Follow¬ 
er Guide 

Loose 

Rattle or click 

Replace with new 
guide 

64 

Valve Stem 
Clearance 

Too much 

Too little 

Click 

Blow-back in car¬ 
buretor 

Set inlet gap .020 

Set exh. gap .025 

65 

Push Rod 
Retention 
Stirrups 

Nuts loose 

Rattle 

Blow-back in car¬ 
buretor 

Tighten nuts 

66 

Crank Case 
Gaskets 

Leak 

Oil leak 

Tighten bolts 
Replace with new 

67 

Cylinder or 
Piston 

No oil 

Poor oil 

Grinding and 
sharp knock 

Repair oil system 
Use best oil 

68 

Piston 

Binding in cylinder 
Worn oval causing 
side slap 

Grind or dull 
squeak 

Dull hammer 

Lap off excess 
metal 

Replace with new 

69 

Oil Sump 

Insufficient oil 

Poor oil 

Grind and squeak 
in all bearings 

Replenish with 
best oil 

70 

Piston Rings 

Defective oiling 

Squeak, hiss, 
grind 

Replace with new 

ring 

Repair oil system 

71 

Crank Shaft 

Defective oiling 

Squeak 

Clean out oil holes 
Use best oil 

Repair oil system 

. 72 

Engine Base 

Loose on frame 

Dull pound 

Tighten bolts 

73 

Water Pipe 

Leak 

Clogged 

Defective gaskets 

Engine heats 

Tighten connec¬ 
tions 

Clean 

Replace with new 









































V-2 Hand Book 


25 


INDEX TO MOTOR DRAWINGS 


Number on 

Fig. V Fig. VI 

Name of Part 

Reference in 
Trouble 
Chart 



Crankshaft Section (1-10) 


3 


Crankshaft Main Journal 

37-71 

4 

4 

Crank Pin 

37-71 

5 


Crankshaft Bearing 

52-38 

6 


Crank Gear 

57-12 

7 


Main Bearing Cap 

54 



Propeller Section (11-20) 


11 


Propeller 


12 


Crankshaft Taper 


13 

13 

Propeller Hub 


14 


Propeller Hub Bolts 


15 


Thrust Bearing 




Camshaft Section (21-30) 


21 


Camshaft Gear 

12-36-57 

22 

22 

Camshaft 


23 

22 

Cam 

11-48 

24 


Camshaft Bearing 

10-58 

25 

25 

Cam Follower 

14 


26 

Cam Follower Guide 

13-63 



Valve Section (31^0) 


31 

31 

Exhaust Rocker Arms 


32 

32 

Intake Rocker Arms 


33 

33 

Exhaust Valve Spring 

23-6 

34 

34 

Intake Valve Spring 

60-23-6 

35 

35 

Exhaust Push Rod 

65 

36 

36 

Intake Push Rod 

65 

37 

37 

Exhaust Valve Cage 


38 

38 

Intake Valve Cage 



39 

Intake Valve 

4 



Ignition (41-50) 


41 

41 

Magneto 


42 


Distributor 



43 

Spark Advance Lever 



44 

Breaker Box 


45 


Magneto Gear 


46 

46 

Spark Plug 

1-26-43 























26 Curtiss Aeroplane and Motor Corporation 


INDEX TO MOTOR DRAWINGS—Cont. 


Number on 

Fig. V Fig. VI 

Name of Part 

Reference in 
Trouble 
Chart 



Carburetion (51-60) 



51 

Combustion Chamber 

46-2 

52 

52 

Carburetor Induction Pipe 

19 


53 

Intake Manifold Connection 

45-24 

54 

54 

Carburetor 

18 


55 

Carburetor Braces 




Lubrication (61-75) 


61 


Oil Pump 


63 


Oil Suction Pipe 


64 

64 

Oil Sump 

69-39 

65 


Crankshaft Oil Tube 


66 

66 

Oil Pan Partition 



67 

Rocker Arm Oil Holes 



68 

Connecting Rod Oil Tube 



69 

Oil Filler Pipe 



70 

Breather Pipe 


71 

71 

Oil Pressure Pipe 


72 


Supporting Web Oil Tube 




Cooling (76-85) 


76 


Water Pump 

42 

77 

77 

Outlet Water Pipe 

40 

78 


Outlet Water Pipe Connection 

25-41 

79 

79 

Inlet Water Pipe 

40 

80 


Inlet Water Pipe Connection 

25 


81 

Cylinder Water Jacket 

40 

82 


Radiator 




Piston (86-90) 



86 

Piston Head 

68-3-20-33-49 



Cylinder and Connecting 




Rod (91-95) 



91 

Cylinder Wall 

67-85-44-22 


92 

Wrist Pin 

50-32 


93 

Connecting Rod 

51 

94 


Connecting Rod Bearing 

53-38 



Miscellaneous (96-100) 



96 

Engine Bearers 



97 

Intake Valve Clearance 

9-64 


98 

1 Exhaust Valve Clearance 

9-64 


99 

Crank Case Lower Half 

55 


100 

Engine Bed Bolts 

































4 - 



13 



Fig. VI 


Fig. V 


Motor Assembly Drawings 


























































































































































































































































































































































































































































































































UPPER DEAD CENTER . 

EXHAUST CLOSES. 


u_i 

X 

h 

CD 

D 

Uj 

I 

H 


LU 

CD 

Q 

_l 

15 

o 

I 

<n 


v5 

z 

U) 

o 

-J 

o 

f- 

(D 

r? 

<E 


LU 

(D 


(n 

(/) 

O 

Q. 


a 


o' 

Uj 


X 

P 

O 

h 



cy 

UJ 

H- 

Z 

Uj 

O 

o 

<x 

UJ 

D 

<y 

LU 

o 

-J 


Fig. VII. Timing Diagram 



















I -2 Hand Book 


27 


MEMO 



28 Curtiss Aeroplane and Motor Corporation 


MEMO 



V-2 Hand Book 


29 


MEMO 



30 Curtiss Aeroplane and Motor Corporation 


MEMO 


« 


THE MATTHEWS-NORTHRUP WORKS, BUFFALO, CLEVELAND AND NEW YORK 





































































































































































































































































































































































































































